Portable data collection devices are widely used in manufacturing, service and package delivery industries to perform a variety of on-site data collection activities. Such portable data collection devices often include integrated bar code dataform readers adapted to read bar code dataforms affixed to products, product packaging and/or containers in warehouses, retail stores, shipping terminals, etc. for inventory control, tracking, production control and expediting, quality assurance and other purposes. Various bar code dataform readers have been proposed for portable data collection devices including laser scanners and one dimensional (1D) charge coupled device (CCD) imaging assemblies, both of which are capable of reading 1D bar code dataforms, that is, bar codes consisting of a single row of contrasting black bars and white spaces of varying widths. Both laser scanners and CCD imaging assemblies are also capable of reading a "stacked" two dimensional (2D) bar code dataforms, such as PDF417, which is comprised of a plurality of adjacent rows of bar code data. The stacked 2D bar code PDF417 includes row indicator patterns utilized by the dataform reader for vertical synchronization to permit reading successive rows of bar code data.
A two dimensional (2D) imaging based dataform reader has been proposed in U.S. application Ser. No. 08/544,618, filed Oct. 18, 1995, now issued as U.S. Pat. No. 5,702,059 on Dec. 30, 1997, and entitled "Extended Working Range Dataform Reader Including Fuzzy Logic Image Control Circuitry". The 2D dataform reader disclosed in application Ser. No. 08/544,618, which is assigned to the assignee of the present application, includes an imaging assembly having a two dimensional array of photosensors adapted to read 2D bar code dataforms (e.g., PDF417, SuperCode, etc.) with vertical synchronization row indicator patterns as well as matrix dataforms (e.g., MaxiCode, DataMatrix, etc.) which do not include vertical synchronization patterns. The individual photosensors correspond to image picture elements or pixels of the resulting image generated with the photosensors are read out after an exposure period or periods. The 2D dataform reader disclosed in application Ser. No. 08/544,618 utilizes an open loop feedback control system including fuzzy logic circuitry to determine proper exposure time and gain parameters for a camera assembly. Application Ser. No. 08/544,618 is incorporated in its entirety herein by reference.
In addition to reading a dataform, it may also be desirable for a portable data collection device to be able to capture a signature. For example, in the package delivery industry, a dataform is attached to each package to be delivered. When the package is delivered to its intended addressee, the package's dataform is read to indicate that the package has been delivered. In addition, the person taking custody of the package confirms delivery by signing a log sheet or a shipping document. Typically, the signature of the person receiving the package is filed with the package delivery records.
In U.S. application Ser. No. 08/623,963, filed Mar. 29, 1996 now issued as U.S. Pat. No. 5,793,033 on Aug. 11, 1998, a portable data collection device is disclosed that includes an imaging based dataform reader with signature capture capability. A signature block was provided in which a recipient would sign his or her name. The signature block was at a predetermined location with respect to a dataform to be read. In one embodiment, the dataform included encoded information regarding the coordinates of the signature block with respect to the dataform. Upon reading the dataform and determining the coordinates of the signature block, data representative of the image of the signature block would be saved. The signature block data would be compressed prior to being transmitted or downloaded to a host computer. Application Ser. No. 08/623,963 is incorporated herein in its entirety by reference.
While the dataform reader disclosed in Ser. No. 08/623,963 is useful, it requires the signature block to be at a predetermined position with respect to a dataform to be read. Additionally, in the embodiment described above, data relating to the position of the signature block with respect to the dataform needs to be encoded in the dataform. This encoding of position data within the dataform necessarily reduces the coding area available for other desired information and represents an additional cost in the dataform creation process.
As such, what is needed is a portable data collection device including a dataform reader having the capability to identify and decode an imaged dataform and, additionally, identify and store an imaged signature area without the necessity of having the signature area being at a predetermined position with respect to a dataform or having signature area coordinate information encoded in the dataform.
Specifically, with regard to the package delivery industry, what is needed is a portable data collection device that has the capability of reading various bar code and matrix dataforms as well as recognizing and capturing an image area corresponding to a recipient's signature. The decoded dataform data and digital data representative of the captured signature may be stored in memory in the device and subsequently downloaded at the end of, for example, the delivery person's work shift. Alternately, the portable data collection device may advantageously be equipped with a radio transceiver and the decoded dataform data and the signature data may be transmitted via radio frequency (rf) signals to a host computer to permit real time updating of the status of a package to be delivered.